This application claims the priority of Germany application 19757063.1, filed on Dec. 20, 1997, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a distance-dependent system for controlling the driving speed of a motor vehicle.
A driving speed control system of this type is known, for example, from U.S. Patent Document U.S. Pat. No. 5,014,200. Such known adaptive driving speed control systems consist particularly of two components. A cruise control system which can keep a speed constant which was defined by the driver; and a sensor system for detecting the distance to the respective vehicle driving ahead.
In the case of distance-dependent adaptive cruise control systems, a defined speed is always kept constant until a defined minimum distance has been reached from the vehicle driving ahead. In the event of a reaching of this defined minimum distance, a speed control takes place such that the defined minimum distance is maintained.
It is an object of the invention to provide a passing aid or lane change aid for a driving speed control system of the initially mentioned type which can reliably be adapted to respective actual driving situations.
The invention is based on the fact that, in the case of distance-dependent adaptive speed control systems, the distance sensor systems are capable of also detecting the traffic in the adjacent lanes. As a result of the intermediate statistical consideration of the adjacent traffic, an actual mean value of the speeds driven by adjacent traffic can be determined. A passing operation or a traffic lane change or an intention to change the lane can be determined, for example, by a turn signal, by a steering wheel rotation signal, by a lateral acceleration signal or by a yaw rate signal. Based on the value of the mean speed of the vehicles in the adjacent lane or in the target lane, an adaptation can take place of the vehicle speed and/or of the distance to the vehicle driving ahead in the momentary traffic lane. The object is a harmonious lane change and a simplified merging into the observed adjacent traffic lane.
If the traffic conditions with respect to the speed and the frequency of the passing vehicles in the adjacent lane are too irregular for being able to form a suitable mean speed value, a predetermined fixed value can, for example, be used for increasing or reducing the speed.
In principle, the invention relates to a traffic lane change between same-direction lanes. The driving direction in the adjacent lanes is detected, for example, by a distance sensor and/or information from a navigation system. If a change to a traffic lane in the opposite direction is detected, the measures suggested according to the invention are suppressed.
If, particularly in conjunction with taking into account country-related variants or, for example, country-related information from a navigation system, a differentiation is made between a change into the left traffic lane or a change into the right traffic lane, it can be detected whether a change is made to a faster or to a slower traffic lane. For example, in the case of right-hand traffic, it can basically be assumed that, when a change takes place to the left traffic lane, a faster vehicle speed is to be expected and, when a change takes place to the right traffic lane, a slower vehicle speed can be expected. The situation would be inverse with respect to the vehicle speed concerning the left and the right traffic lane if the information of the country-related variant, for example, in South Africa or Great Britain, were to indicate left-hand traffic.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.